I have 10 websites with different PHP related platforms like in Drupal, Joomla, WordPress and Core PHP etc (Even includes sub domains also).
I want to create one new website with Registration and login functionality in Core PHP or else any framework. I want to implement single sign on functionality through this latest web site. So that can any one let me know the process to finish this.
If you are looking for a pre-built single sign-on system to integrate with your projects, you may want to check out:
http://barebonescms.com/documentation/sso/
The SSO client can be integrated as a plugin into Drupal, Joomla, WordPress, etc. Basically, override their login system with the SSO server/client system. Finding plugins for it at the moment is a bit difficult since it is relatively new software.